Disclaimer: I do not own Yu Yu Hakusho or any of these characters.

Warning: Story contains yaoi (male/male) of a graphic nature.

Summary: Yusuke has to deal with the backlash of Kurama's recent transformation.

(A.N. Takes place just after the semifinals of the Dark Tournament. In this story Yusuke wakes up a few hours before Genkai's fight with Toguro, but is still delayed.)

Heat

Yusuke sighed as the showers hot water soothed his aching muscles. Most of his injuries from his test had healed as a result of his mastery of the Spirit Wave, but that didn't relieve soreness. Blood and grime flowed down the drain as the remnant of the cave left Yusuke's body. When he finished Yusuke simply wrapped a towel on around his waist and went to his assigned room to collapse on his bed.

"Genkai wasn't kidding." Yusuke groaned as he rolled on his back and stretched. "That orb kicked my ass, but it was worth it." He held his hand up to look at it before running it threw his limp locks. "I'm exhausted, but still... I can feel her power."

Distracted by the flow of new energy within his body Yusuke didn't notice the door to his room opened until he heard someone stumble inside. Sitting up he was confused to see the usually graceful Kurama supporting himself against the door frame. Kurama was breathing hard and his body shaking.

"Kurama!" Yusuke jumped up in order to help support his friend. "What's wrong, are you hurt?"

"Yusuke..." Kurama groaned and wrapped his arms around Yusuke's waist, resting his head on Yusuke's chest. "Please I- I need to..."

"What? You need to what?" Yusuke gently tried to shift Kurama to get a better look at his face, but the fox demon only tensed and held the spirit detective closer. Yusuke was even more confused as he noticed the flush barely visible on the bit of face not burrowed in his chest. "Kurama, are you sick?"

"No, I-" Kurama kept panting as he seemed to struggle to find the proper words. "It's so hot."

"Hot?"

Yusuke's confused exclamation was answered by a harsh shove and he suddenly found himself back on his bed. The flushed fox demon hovering over him. Now that Yusuke had a more clear view of Kurama's face, he could see the glazed look of hunger in his eyes. Something that immediately put the spirit detective on edge.

"Kurama wh-"

Yusuke was cut off as something gripped his wrists tightly and pulled them together above his head. A startled look told him he was being held captive by a cluster of thin but strong vines. He immediately began to tug at his restraints.

"Hey! What the hell do you think you're doing!"

"I'm sorry." Kurama spoke in a breathless, almost pleading voice. "Please, I need it. The box... The box..."

"What box? And will you untie me already." Yusuke growled and continued to pull at the vines. "What the hell has gotten into you."

"Yo...ko. I became Yoko..."

This statement gave Yusuke pause as he took in the fox demon's appearance once more. Kurama was flushed, with sweat running down his cheeks, and glazed eyes. He was breathing hard and trembling. Looking down he also had a...

Fuck!

*Flashback Sometime during the two months before the Tournament*

"Time for another history lesson, slacker." Genkai glared as her apprentice only looked half interested. "In order to survive, you must know your enemies weaknesses!"

"Yeah, yeah, I get it Grandma." Yusuke mumbled. "No need to bite my freakin head off."

"Dimwit." She grumbled before sighing and continuing with the lecture. "Many different kinds of demons go threw a phase known as heat. The demons that go threw heat experience hyper sexual desire and can become lost in the need to relieve the heat, reducing some of the most reasonable demons to rutting animals. This is very similar to the heat experienced by animals, such as cats and dogs, but usually far less often. Also differing from the typical animal heat, a demonic heat can only be relieved threw sexual intercourse. The longer intercourse is delayed, the more wild and desperate the demon becomes for relief."

"..." Yusuke was blushing as he awkwardly avoided Genkai's gaze. "... I need to know this why?"

"Simple." Genkai smirked as her apprentice shifted uncomfortably. "Demon's can be vulnerable at this time as they will be willing to sleep with anyone they are semi attracted to, male or female, regardless of their prior relationship. This can make approaching an enemy much easier if you are blessed with good looks and, believe it or not, you are." Yusuke grinned, but Genkai just rolled her eyes. "However, the heat can also make demons even more dangerous as the lack of restraint can make them stronger and unpredictable. You would have to constantly be on guard, even around your little demon friends."

"You mean Hiei and Kurama?"

"Yes. While I am uncertain as to whether or not halfbreed" Yusuke glared a little at what he knew to be a derogatory term, "Koorime have a heat cycle, I know for a fact foxes do. His current human form may interfere with the cycle, but the older and stronger he becomes, the more likely Kurama is to go into heat. Thus making him very dangerous to all of the humans around him, including you. If he couldn't find a willing participant fast enough, he may resort to rape."

"But Kurama wouldn't-"

"Under normal circumstances, no." Genkai cut Yusuke off. "He wouldn't, foxes have far too much pride in their skills of seduction to force themselves on another, when in complete control. However, during his heat he would not be in control." Genkai looked Yusuke in the eye with a serious expression on her face. "Should either Hiei or Kurama go into heat it will fall to you to make sure they do not cause any harm. You may even have to offer yourself in order to minimize the damage."

Yusuke just gaped as Genkai walked off.

*End Flashback*

Aw shit! Why does Grandma always have to be right! Yusuke's mind screamed as he tensed an forced himself to stop tugging against Kurama's vines. Well at least I'll get to see if those rumors about foxes are true.

"Hey Kurama." Yusuke swallowed as the fox's gaze snapped back into focus as the spirit detectives voice knocked him out of what seemed to be an attempt to gain some control back. "Are you in heat?"

"Yes." Kurama's eyes looked pained as he lifted a trembling hand to Yusuke's chest. Slowly dragging it down to the loosened towel. "Please, Yusuke."

"Right." Yusuke swallowed the lump in his throat as apprehension buzzed threw his body. "Just... just take it easy on me, okay." He swallowed again as Kurama turned his startled green gaze back to Yusuke's face. "I've never done this before."

The utter relief on Kurama's face was worth the heated flush on his own cheeks. Yusuke tensed and his flush darkened as the fox pulled the towel away, but he forced himself to relax and allow the fox to part his legs. Kurama stripped his yellow chinese top and white undership before settling in between the spirit detectives legs. Yusuke closed his eyes and tried not to focus on the delicate hands stroking his thighs, but his eyes shot back open when he felt warm breath over his limp length.

"Wha-"

Yusuke could do little more than let out a startled exclamation as the fox demon swallowed his length, engulfing it in a warm, moist, paradise. As a virgin Yusuke had never experience anything more intense than his own hand prior to this, but now he realized just what he'd been missing. Kurama's skilled mouth quickly brought the young spirit detective's length to full attention and beyond. So lost in his ecstasy Yusuke barely felt it as something thin and slick that he could only assume was Kurama's finger, slipped into his entrance. It was foreign and strange, but not altogether unpleasant, especially not when combined with an experienced tongue skillfully manipulating Yusuke's erection. When the second finger entered Yusuke felt the skin stretch uncomfortably, but this was lost as he felt his balls tighten in a familiar fashion.

"Kurama I- I'm gonna..." Yusuke tried to gasp out a warning. "Gonna cum!"

The fox demon ignored the warning and only increased his suction as he gently stretched Yusuke's hole. Yusuke tried to hold it in, but lost the battle when Kurama's fingers brushed something inside. The sudden shock wave of pleasure sent him hurdling over the edge.

"Kurama!" Yusuke shouted and arched his back, emptying his load into the waiting mouth. His mind to far gone in pleasure to notice the burning sensation as Kurama ease a third finger into his hole. "Nng."

As Yusuke lay basking in the afterglow of his orgasm Kurama slipped his fingers out of Yusuke's hole. The fox demon stared at Yusuke's flushed face before leaning forward and claiming the spirit detectives lips in a deep kiss. Yusuke was startled but quickly granted access to his mouth, trying to reciprocate but unable to keep up with the skilled tongue. The taste of his own essence was not something Yusuke particularly liked, but it wasn't bad enough to deny the fox what he wanted.

Once he had resigned himself to serving as Kurama's release, Yusuke had expected the encounter to be more awkward and painful then anything else, but so far all he'd felt was pleasure. Yusuke was glad his friend maintained enough control over himself not to rush things, thus saving Yusuke a great deal of pain. Although Yusuke had a feeling the rest would feel good as well, he couldn't quite stop himself from tensing when Kurama pulled back and flipped the spirit detective over. After a bit of rearranging Yusuke found himself on his knees with his ass in the air, his bound hand keeping his arms stretch forward and head down.

"Relax." Yusuke felt something hot and blunt rubbing his stretched hole. "Please I- I don't want to hurt you."

"Sorry." Yusuke apologized and took a deep breath, trying to calm himself down and relax his tense muscles. "Right, I'm good."

As soon as the words left Yusuke's mouth he felt Kurama bare chest lean against his back, a soft kiss pressed into his shoulder as long red hair fell into his line of sight. That was all the warning Yusuke got before Kurama's erection breached his entrance. Kurama tried to be slow, but once the tip passed the tight ring of muscle he jerked forward, burying his erection completely. Yusuke grunted as the hot flesh stretched his hole painfully, but remained relaxed and focused on breathing.

"S-sorry." Kurama groaned as he forced himself to remain still and allow his friend to adjust to the intrusion. "It's so... so good."

The two remained like this for a few moments as the pain of penetration dulled to simple discomfort. Yusuke grunted again and shifted a bit to find comfortable, but stopped when he heard Kurama groan in pleasure and give a small, experimental thrust. The sensation was completely new to Yusuke and, while not amazingly so, did feel somewhat good.

"I- I think we're good." Yusuke shifted again, this time more deliberately. "Go ahead."

Needing no other words of encouragement Kurama began thrusting. Yusuke had been hoping to be eased into the motion and was a bit startled when Kurama set a hard, fast pace. The grunts and shuttered cries coming from the fox demon told the spirit detective his friend was too far gone at this point for gentle. Not that it mattered as the detective was assaulted an unexpected wave of pleasure cause by the fox repeatedly hitting the same spot from earlier.

"Mo-more! There!"

"Hng!"

Kurama couldn't respond with words, but he did adjust his grip on Yusuke's hips to ensure he hit the same spot over and over. Both members of team Urameshi were reduced nothing but incoherent grunts and moans as they descended further into the pleasure of the rut. The foxes skilled hands once again finding Yusuke's erection, thus doubling his pleasure.

"Ku-kurama!"

Yusuke yelped as he felt his balls tighten once more and he tumbled into a second, mind blowing orgasm. As his passage tightened Kurama's thrusts faltered and became more erratic. The foxes remaining hand on the spirit detectives hip tightened enough to leave a bruise as Yusuke felt warm fluid pooling inside.

Aw hell, need another shower now. Was all he could think as his knees collapsed and his body trembled with pleasurable aftershocks. His numb mind barely felt it as Kurama withdrew his now limp length. Sticky... With that Yusuke fell into unconsciousness.

(A.N. I rarely see fic about this bit of time and when I do it's usually a rape fic involving Karasu. Usually people pair Kurama with Hiei, but I'm a fan of mixing and matching Yusuke, Hiei, and Kurama in a variety of ways, although my favorite is a threesome. At this point I don't know if I'll stop here or write more. If I do continue expect to see a lot of Hiei.)